Apparatus for screening materials



Aug. 31, 1926. I 1,597,826

' M. P. REYNOLDS APPARATUS FOR SCREENINC' MATERIALS Filed March 29, 19194 Sheets-Sheet 1- l I/v VEA/T'O/C Aug. 31, 1926. 1,597,826

M. P. REYNOLDS APPARATUS FOR SCREENING MATERIALS Filed March 2 9, 1919 4Sheets-Sheet 2 i l a v 2 u 1 1 Q l 0 3/ O Q El/o O O E 55 I 55 f Z? 8 iZ I A? :3

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M. P. REYNOLDS APPARATUS FOR SCREENING MATERIALS Filed March 29, 1919 4Sheets-Sheet 5 Aug. 3 1926. 1,597,826

M. P, REYNOLDS APPARATUS FOR SCREENING MATERIALS Filed March 29, 1919 4Sheets-Sheet 4 HA/EA/TOE/ A TTQ ENE m5 Patented Aug. 31, 1926.-

UNITED STATES PATENT OFFICE.

MORLEY PUHBHON REYNOLDS, OF CLEVELAND, OHIO, ASSIGNOR TO 'LIEHE- W. B.TYLER NMPANY, OF CLEVELAND, OHIO, A CORPORATION 01? OHIO.

APPARATUS FOR SCREENING MATERIALS.

Application filed March 29, 1919. Serial No. 285,953.

The present improvements, relating, as indicated, to screening machines,are more particularly directed to an improved means for securing a moreeffective vibration or movement of a screen surface in order to agitatethe material passing thereover and cause the same to continuouslyclassify itself in such a way as to present the smaller particles to thesurface of the screen. Another object of the invention is the provisionof asimple but effective electro-magnetically operated vibratingmechanism. To the accomplishment of the foregoing and related ends, saidinvention, then, consists of the means hereinafter fully described andparticularly pointed out in the claims.

The annexed drawings and the following description set forth in detailcertain mechanism embodying the invention, such disclosed meansconstituting, however, but one of the various mechanical forms in whichthe principle of the invention may be used.

In said annexed drawings Fig. 1 is a side elevation of a screeningmachine constructed to embody my improvements therein; Fig. 2 is alongitudinal section through the screen and frame; Fig. 3 is atransverse section through the vibrating mechanism; Fig. 4 is a section011 the line 4-4, Fig. 3; Fig. 5 is a transverse section showing amodification of the vibrating means; Fig. 6 is a side elevation of thesame; Figs. 7 and 8 are views corresponding-to Figs. 5 and 6 showingstill another modification of the vibrating means; Fig. 9 is adiagrammatic view showing the connections for theeIectro-magnet of Figs.7 and 8; Fig. 10 is a longitudinal section through my preferred form ofvibrating mechanism; and Fig. 11 is a section on the line l1-11, Fig.10.

Before proceeding to the description of my invention it may be desirableto briefly outline the faults which have heretofore been experienced invibrating mechanism. The chief objection in mechanical vibratorshas beenthat the proper speed of vibration could not be applied. It ismechanically possible to strike a screen surface at a sufficiently highrate of speed to secure really good results, but practical structuralconsiderations have limited the rate of speed and character of impulsesthat produce the most effective screening action. Electrical vibrationhas been tried heretofore in order to obtain high speed, but withoutresults that have caused actual adoption of an electrical vibrator inany screening; apparatus now in use. From my experiments I am convincedthat the failure of former electro-magnetic devices has been due chieflyto the fundamentally wrong character of vibration produced.

In passing material over a screen, tonnage and accuracy are theessential considerations and require constant agitation of the materialin such a way as to present new particles to the meshes of the screen,but this must be done so as to cause the smaller undersize particles tocontact the screen surface, and not the oversize, that is, the largerparticles coming to the top and the smaller particles, working down intoa position to contact the screen and work through the meshes thereof.This necessary act-ion is caused by an improved apparatus, which rovidesa really efficient screening action y the associated presence of themechanical features which I have found essentiall Referring now to Fig.1, there is shown a screening machine of a well-known type, in which.the casing 1 is mounted in inclined position and is provided with aninclined screen surface 2 held in a suitable frame 3 in the casing 1.The other features of the screening machine itself need not be describedin detail as the machine in general differs in no way from the usualinclined screening machine except in the features which are hereinafterto be described.

In Fig. 2 I have shown one convenient and efficient means of mountingthe screen cloth in the frame in such a way as to maintain the screencloth at a fixed drumhead tension and in a truly vibratory conditionthroughout the screening area. This means consists, as shown in Fig. 2,of an S-shaped hook-like strip 4, the inner end 5 of which is re-bentand clamped over the turned-in edge 6 of the screen cloth, which isreinforced by a stiffened strip 7 of fabric or similar material. Theouter edge 8 of the hook-like strip is in turn fastened over one edge ofan angle iron 9, and the two angle irons 9 and 10 at the opposite sidesof the frame areconnected together and are s aced in any desiredrelation by means of a lusting bars 11 threaded into right and efthandthreaded sockets 12 in the angle irons on the two sides of the frame. Byad ustment of the bars the angle irons may be spread apart and in thisway an even uniform tension is put u on the screen surface, and thetension may be increased to such a point that the screen surface isunder avibratory, drumhead tension.

Mounted longitudinally and centrally upon the screen surface is asuitable stri of metal 15. The stri of metal is rigidly fastened,-either by lting or some other suitable means, to the screen surfaceitself and extends over the entire length of the screen. This metalstrip may be termed a distributing strip and its action is to distributethe impulses conveyed to it over the entire screen surface, as it hasbeen found that a very much better screening action can be secured ifthe vibratory action can be transmitted to all parts of the screen, andsuchan action cannot be secured on li ht screen cloth by a singlevibratory mec anism unless some such means of distributing the impulsesare employed. On heavy screen cloth where the wires are themselves ofconsiderable size, it is perhaps unnecessary to use any additionaldistributing means, as there the wires themselves are sufiiciently rigidto serve as distributing strips for transmitting the vibratory impulsesthroughout the screening area of the screen cloth.

It is important that the screen cloth be under a vibratory and uniformtension at all points throughout its area and also that the vibratoryimpulses be transmitted to all parts of the screen by means of adistributing strip, such as I have described, or a similar functioningmeans. Without these two conditions the action of the vibratory meanswhich I will now describe, is not satisfactory and capable of givin thebest results either in the tonnage 0 material handled or in the accuracyof the separation.

The means for limiting the movement of the armature act to bring to asudden stop both the armature and screen upon the travel under theinfluence of the elect-rd magnet, and as this travel is ra id the suddenstoppage of the armature and screen, which is caused by the engagementof the armature against the surface of the core, jars the screen verysharply. This jar is transmitted to the screen upon movement of thearmature and is important, as it overcomes the main difficulty which hasheretofore been found with electro-magnetic vibrators for screeningmachines. The difficulty in question is that in electro-magneticmachines as used in the past, while an extremely rapid vibration hasbeen given to the screen surface, there has been no striking or jarringaction transmitted to the screen to cause the material passin thereoverto be agitated sufiiciently for t e purpose of making the desiredseparation. In such machines the screenin action has been very muchhampered by tie fact that the material was not properly agitated at eachimpulse or movement of the screen to bring the larger particles to thetop and allow the smaller particles to go to the bottom and work theirway through the screen surface. The present means for limiting the rangeof action of the armature and screen surface serve to impart thenecessary jarto the screen and to cause the larger particles or oversizeto leave the surface and the smaller particles or undersize to travelclosely to the surface of the screen.

A rapid vibration of the screening surface is also necessary to securethe highest efliciency, both in tonnage of material and in accuracy ofseparation. In screening machines employing mechanical means forvibratin the screen, which have almost invariab y taken the form ofhammers striking against the screen surface or means for jarring thescreen surface longitudinally the rate of vibration has usually beenthree to six hundred vibrations a minute. This rate of vibration is tooslow to secure the best screening action for most uses, and while I amnot prepared to specify any exact speed, the best speed in each casewill depend upon a number of factors, such as the size of wire and sizeof opening in the screen surface, and the size and weight of materialpassing thereover and the condition of material as to moisture. I havefound that the best results'cannot be secured by vibration of less than800 vibrations a minute, nor more than 4000. Tests indicate that theminimum and maximum speeds are approximately as given above. Byelectromagnetic means any speed found necessary to the most eflicientvibration can be applied. The working range of the screen between itsuppermost and lowermost positions need never be more than aboutone-eighth of an inch, irrespective of the kind, weight or size ofmaterial passing over the screen, and irrespective of the character orsize of the screen itself. The amount of travel or working range of thescreen should, however, be determined according to the character ofmaterial to be screened, and the size and strength of the screen usedwhen the machine is first installed and tested and it should not benecessary to thereafter use this adjustment so long as the same kind ofmaterial and the same character of screen are used.

The adjustment for difi'erent kinds of material may be made, of course,while the machine is in operation, but as a matter of practice it neednot be, as the best vibratory action of the screen can easily bedetermined before material is passed over it at all.-

For determining the point of best vibration, a removable door is mountedin the top of the machine, and to adjust the vibration, the vibratorymeans are operated before material is passed over the screen, and theoperator, by opening the door 55, can place his hands upon the screenand can thus adjust the hand wheel 37 until the proper action issecured. It is extremely difficult to describe in words how to determinewhen the vibration is satisfactory, but in practice it is easilydetermined by putting the finger tips to the screen.

My improved electromagnetic means are shown in various forms in Figs. 3,4,- 5, 6, 7, 8, 9, 10 and 11, and the form. which I have found to givethe best results is that shown in Figs. 10 and 11. In this latter formthe electromagnetic means are mounted in a casing 22, open at its bottomand supported upon a bridge 29, extending across the frame 0 themachine. The coils of the magnet are mounted in the casing while thearmature 25 is mounted on a casting 104. Formed as a part of the casting104 is an extending socket 105, in which is removably attached a rod106, having a threaded upper end for convenient insertion in, andremoval from,

this socket 105. This post or rod 106 passes through an opening in abridge 29 and is snugly fitted in an opening in a leather diaphragm 107which is bolted on the under side of the bridge to entirely close theopening therethrough. A light plate 108 is mounted below and around theouter edge of the diaphragm. The rod 106 has a flange 109 mountedagainst the diaphragm. In this way the rod is securely fastened to thediaphragm, and as a very slight movement of the armature is required, aswill be more fully explained hereafter, the diaphragm has sutlicientflexibility to move with armature and rod 106.

Mounted on the distributing strip 15 on the screen is an invertedU-shaped bracket 110, which is provided with an opening in its upper orflattened portion, into which the rod 106 passes, where it is adjustablsecured by means of washers 111 and loc nuts 112. The adjustment of therod 106 in the bracket is necessary in many cases to make up for thevariations in the position ofthe bracket caused by the differentthicknesses of screen which are used, and by this means a very widelatitude for adjustment is provided.

Mounted on a plate on the bridge 29' is a second strip of leather, whichis covered by a plate 114, both the plate and strip being then securedby means of screws 115 to the cover plate. This strip and the plate arenot attached to the rod 106 and do not move with it, but merely haveopenings through which the rod 106 passes and serve as a guide for thereciprocation of this member.

Mounted in an extension 36 on top of the casing is an adjustable rod 33which may be adjusted by means of a hand wheel 37 externally of thiscasing and may be locked in that position by means of a lock nut 38.This adiusting member 33 is provided with a flange 34, against which ismounted a spring 35 pressing upon a socket 32 on the upper end of a rod31 which passes down" through the center of the electromagnet intocontact "with the upper face of the armature 103. This adjusting rodserves to determine the working range of the armature and of the screen,and may be adjusted to increase or decrease the amplitude of vibrationof the screen surface. By increasing the tension on the spring 35 theforce, acting to return the armature to its lowest positional-1d also ofcourse the screen, is increased, and this increased force will drive thescreen and armature downward upon the release of the armature by theelectromagnet.

Theelectro-magnet is operated by any suitable kind of intermittent orpulsatin current in order to alternately energize and de-energize theelectro-magnet and alternately attract the armature and screen.

In Figs. 3 and 4; I have shown a slightlymodified type of vibratingmeans, in which a bracket 26 is attached to the distributing strip 15 asin the previously described form and is then carried upwardly on eitherside of the bridge 29 in slots 28 which are formed therein and directlyattached to the armature 103.

In Figs. 5- and 6 I have shown still another modifiation of theelectro-magnet, in which the armature is pulled downwardl instead of;upwardly as in the preceding orms, an armature 51 being mounted abovethe electromagnet 50, and being connected to the screen or distributingstrip in the same manner as in Figs. 3 and 4. In this form two rods 53are attached to the upper 'side of the armature and carry at their upperends a plate 120 against which is positioned a spring 57. This spring 57is held between the plate and a socket 56 which is carried on theadjusting rod 33, which may be adjusted by the external hand wheel 37,as previously described.

In the vibrating means illustrated in the figures already described itis intended that a sharp jar shall be given to the screen upon itsreaching its limited movement in one direction, which in the case of thevibrators of Figs. 9, 10, 3 and 4 is its upward position, and in thecase of the vibrator of Figs. 5 and 6 its lowermost position. To securethis jarring action, which is necessary to secure a proper and eflicientscreenin action, I cause the armature to be broug t directly intocontact with the core of the electromagnet, as this forms the mostconvenient method of securing this sharp jar without additionalmechanism. It W111 be recognized of course that other means for securinga sharp jar can readily be provided, and in Figs. 7 and 8 I have shownsuch a means.

In Figs. 7 and 8 I have shown a doubleacting electromagnet consisting ofspaced electromagnets 60 and 61, operating to reciprocate an armature62, which is mounted between the electromagnets and attached to thevibrating strip 15 on the screen by means of a bracket 63. In this formthe armature is floated between the electromagnets and need not contacteither of them as the armature is provided with lateral extensions orlugs 69 and 70 moving between adjustable stops 64 and 65. and 66 and 67,which are carried in suitable extensions of the housing 22. Byconvenient adjustment of these steps 64, 65, 66 and 67 the range ofaction of the armature can be accurately set and the armature can bejarred upon each u ward and downward movement, that jar 0? course beingtransmitted directly to the screen surface through the bracket 63 andthe distributing strip 15.

In Fig. 9 I have shown the circuit connections for this doubleelectromagnet. In

this circuit diagram there is shown a suitable source of current 81,such as a generator, from which extends lines 82 and 83 to the coils 60and 61, respectively. From these coils extend lines or contacts 71 and74.

Other lines 72 and 73 are connected to the lines 83 and 82, resectively, and all of the connections 71, 72, 73 and 7A are arranged tobe contacted by a rotating switch or commutator 80, which may beoperated by any suitable means. The rotation of this switch 80alternately connects the coil 60 with the source of current supply andthen the coil 61, and causes an alternate energizing of the coils 60 and61.

Other modes of a plying the rinciple of my invention may be employedinstead of the one explained, change being made as regards the mechanismherein disclosed, rovided the means stated by any of the fol owingclaims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as myinvention 1. In screening apparatus, the combination of a screentensioned to a uniform drumhead tension, means adapted to vibrate thesame at high speed, means adapted to bring the screen to a jarring stopupon each vibratory impulse thereof, and a distributin member mounteddirectly on the screen and extendinge from side to side thereof, saidmember ing adapted to distribute the jar caused by such stop throughoutsuch screen.

2. In screening apparatus, the combination of a screen tensioned to auniform drumhead tension, means adapted to vibrate the same at highspeed, means adapted to bring the screen to a jarring stop upon eachvibratory impulse thereof, and a longitudinally disposed distributinstrip mounted directly on said screen an adapted to distribute the jarcaused by such stop throughout such screen.

3. A vibrating apparatus for screens comprising an electro-magnetadjacent to a screen, an armature mounted directly on said screen, meansada ted to operate said electro-magnet intermlttently and at a high rateof speed, and stop means mounted to be engaged by said armature uponmovement thereof.

4. A vibrating apparatus for screens comprising an electro-magnetmounted centrally and duectly adjacent to a screen, an armature mountedon said screen, means adapted to operate said electro-magnetintermittently and at a high rate ofspeed to move .said armature in onedirection only, and means adapted to assist in returning said armatureto its initial position.

5. A vibrating apparatus for screens comprising an electro-magnetmounted adjacent to a screen, an armature mounted centrally and directlyon said screen, means adapted to operate said electro-magnetintermittently and at a high rate of speedto move said armature in onedirection only, and resilient means adapted to assist in returning toinitial position said armature and said screen.

6. A vibrating apparatus for screens comprising an electro-magnetmounted centrally and directly adjacent to a screen, an armature mountedon said screen, means adapted to operate said electro-magnetintermittently and at a high rate of speed to move said armature in onedirection only, resilient means adapted to assist in returning toinitial position said armature and said screen, and means for varyingthe pressure exerted by said resilient means.

7. A vibrating apparatus for screens comprising an electro-magnetmounted centrally and dlrectly adjacent to a screen, an armature mountedon said screen, means adapted to operate said electro-magnetintermittently and at a high rate of speed, and said electromagnet beingadapted to actuate said armature and screen away from material passingthereover.

8. A vibrating apparatus for screens comprising a casing open at oneside, an electro magnet mounted in said casing, an armature also mountedin said casing, a flexible diaphragm closing the open side of saidcasing, said armature being attached to said dia- 531m and means alsomounted on said up ragm. and adapted to rigidly connect the same with ascreen.

9. The combination with a screen having I a bracket mountedthereon, of avibrating device comprising a an electromagnet moun flexible diaphragmclosing open at one side,

the open side of in said casing, a 1919 g MOR EY PUNSHON REYNOLDS

